If you act right now, you can book a campsite for the Fourth of July at one of nine campgrounds at gorgeous state parks in the greater Bay Area. Sites at three other campgrounds in the region are available first-come, first-served.

You also can book a cottage or hotel room at the rustic and historic Columbia State Historic Park near Sonora.

If you don't have your plans wired for the Fourth of July weekend, you still can salvage the three days. You need to act fast, and plan to travel farther or to venture to lesser-known or less stellar destinations.

The renowned sites have been booked for months. They include Yosemite, Tahoe, Monterey, Big Sur and Point Reyes. If you don't have reservations, forget it. Even the large campgrounds at Jedediah Smith Redwoods and Prairie Creek Redwoods in the Redwood Empire, a 350-mile drive one-way from the Bay Area, are 100 percent booked.

The best news is that the weather outlook is for sunny skies and temperatures peaking in the low 80s for the holiday weekend in the high Sierra. There are no significant forest fires; the Shelly Fire in the southern Sierra (west of Lake Isabella) was 100 percent contained this week, and the smoke will not be a factor by the Fourth of July.

Although many big reservoirs popular for water sports are low, those who venture to smaller lakes in the high country will find many that are full (125 detailed in Sunday's Chronicle and archived at www.sfgate.com/outdoors).

Here is the region-by-region outlook for the biggest vacation weekend of summer:

Greater Bay Area

The region has 275 recreation sites for day use. You could throw a dart blindfolded at a map of the Bay Area to pick one and not go wrong. With a lot of people heading out, one strategy is to do the reverse and head in: The San Francisco waterfront, from Fort Mason west past Marina Green, Crissy Field and on through the Presidio past the Golden Gate Bridge to Baker Beach, China Beach or Lands End is all "can't-miss great," as we call it. Across the region, many camps are still available, and compared with other areas, provide the opportunity to awaken at a launch point for adventure.

Coast

The weather outlook for the coast calls for a series of sunshiny days. Some years, it is so foggy over the Fourth that any fireworks shot into the sky at night disappear into low-hanging stratus. With the perception that most lakes in the foothills and Sierra are low and poor destinations, many are instead turning to the coast. Reservations for campgrounds and lodging are long-booked at most destinations within 150 miles of San Francisco. The camps at Point Reyes and Monterey Bay were booked full last winter. One note: Roads to the coast are two-laners, so for day trips, get up early to beat the traffic.

Sierra Nevada

The dozens of small lakes nestled in remote national forest, ideal for those with an SUV loaded with camping equipment and a kayak or two, can make your weekend. Even these will be popular, and it will take a Thursday arrival, or at latest Friday morning, to nail the best campsites. The best bets for vacant campsites are the Trinity Divide, northern Plumas County near Bucks Lake, and anywhere it takes a 4-wheel-drive or a hike to get there. At Yosemite, every campsite and room available by reservation was taken long ago; at Tahoe, every place I checked, same thing. At Tahoe or Yosemite, have a reservation or a personal "in," or stay out.

Redwood Empire

Between state parks with campsites still available and lesser-known campgrounds located on streams or at trailheads in Six Rivers National Forest, you can find a spot, any day of the year. In many areas on the coast, you also can hike to remote areas of beach and camp to salvage the trip. But get this: It's 320 miles from San Francisco to Prairie Creek Redwoods, 363 miles to Jedediah Smith Redwoods, yet each is 100 percent booked.

North state

Like the Redwood Empire, it's a long drive for the reward of decent prospects. Lake Siskiyou, a centerpiece, is 100 percent full. Consider 14,179-foot Mount Shasta, still with enough snow on the primary climbing route, and weather projected to be great for a summit attempt. The Upper Sacramento River is low, but there has been a surface hatch at dawn and dusk for fly-fishing. Giant Shasta Lake is only 43 percent full so about 80 percent of houseboats are available. For those with SUVs, the Trinity Divide has many small lakes, some that require high-clearance 4-wheel-drive to reach, and some that take short walks to lakeside campsites.

Valley & foothills

After temperatures pop into the low 100s this weekend in the Sacramento Valley, the outlook calls for temps reaching the more tolerable low 90s for the Fourth of July weekend. That is still hot enough to scare off a lot of folks. Lake levels are like a random-patched quilt.

Gold Country

Highway 49, the long, often-twisty two-laner, is likely to be filled with cars and not much fun. The stretch from Auburn to Grass Valley is a perpetual bad dream because of the zoo-like procession of people who think they are stock-car drivers. From Sonora to Mariposa, it's a twisty nightmare, especially on a motorcycle, stuck behind an RV. Most of the lakes are low, but boating is popular in this region; expect crowds anyway. A gem that is overlooked, over and over, is the historic Columbia Hotel and Cottages near Sonora (and New Melones Reservoir), a state park unit which still has plenty of space.

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